In many jobs and activities it is highly desirable to provide a safe, secure, and easy to use way to both climb and descend a rope. This includes tree work, rock climbing, rescue work, and tower or building repair or maintenance. The nature of tree work in particular also requires that such systems/devices/apparatus allow for movement of a climber both vertically and horizontally within a tree. Traditional systems rely on friction hitches or prusik knots applied to a doubled length of rope, which runs over a limb or other anchor point in a dynamic 2:1 fashion. This is referred to as doubled dynamic rope technique (DdRT). More modern systems utilize a single length of rope affixed at one end to a limb or other anchor point in a static 1:1 fashion. This is referred to as single rope technique (SRT). The climber utilizes a device or apparatus that allows movement and positioning along the non-anchored leg of the rope. Due to the 1:1 nature of SRT, traditional friction hitches and prussic knots do not function satisfactorily. This necessitates the use of a mechanical element or device.
Since the introduction of SRT to the field of tree work, there is a need for a single device, which can not only be used to both ascend and descend in a safe manner, but also to do so in a simple, easy manner, using only one hand to tend the ascender/descender mechanism. In addition, there is a need to provide a device of this type that is durable, automatically clamps when weight is applied, easily and quickly attaches to, and detaches from the rope, is easily adjusted for a range of rope sizes and constructions, does not require the use of removable pins or parts, and is compact in size and comfortable in the hand. It is further desirable to be able to use a single device employing either SRT or DdRT without modification.